Fuel cell electrode with redox catalyst

• US 7,615,293 B2
• Filed: 09/01/2004
• Issued: 11/10/2009
• Est. Priority Date: 10/03/2003
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Farneth, William E., Harmer, Mark Andrew, Damore, Michael B.
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): WALKER, KEITH D
• Application Number:
  US10/932,371
• Publication Number:
  US 20050074663A1
• Time in Patent Office: 1,896 Days
• Field of Search: None
• US Class Current: 429/401
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 2250/30 Fuel cells in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8647 consisting of more than one material, e.g. consisting of composites
• CPC Class Codes: H01M 4/8673 Electrically conductive fillers
• CPC Class Codes: H01M 4/8807 Gas diffusion layers
• CPC Class Codes: H01M 4/8814 Temporary supports, e.g. decal
• CPC Class Codes: H01M 4/8828 Coating with slurry or ink
• CPC Class Codes: H01M 4/90 Selection of catalytic material
• CPC Class Codes: H01M 8/0206 Metals or alloys
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0247 characterised by the form characterised by a channel configuration H01M8/0258
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: H01M 8/16 Biochemical fuel cells, i.e. cells in which microorganisms function as catalysts
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

The invention is directed to an electrode, suitable for use in a fuel cell, consisting of a microporous current collector incorporating a multitude of domains and wherein each domain contains soluble redox catalyst.

Claims

1. A fuel cell electrode comprising a porous current collector comprising an electrical conducting material in contact with a multitude of domains, each domain containing:

a) a redox catalyst; and

b) an electron transport mediator;

wherein the redox catalyst and electron transport mediator are in fluid association with each other within the domain and wherein the redox catalyst and the electron transport mediator are bounded in the domain by the porous current collector and a containment material, wherein said containment material is selected from the group consisting of carbon, silica, titania, alumina, polyesters, polyamides, polyimides, fluoropolymers, polyelectrolytes, organosubstituted silica, silicones, organosubstituted titania, and organo metal oxides.

2. A fuel cell electrode according to claim 1 wherein the electrical conducting material is selected from the group consisting of:

carbon paper, carbon paste, carbon nanotubes, carbon particles, conducting polymers, noble metal particles and conducting metal oxide particles.

3. A fuel cell electrode according to claim 1 wherein the diameter of the domain is less than 100 μ

m.

4. A fuel cell electrode according to claim 1 wherein the diameter of the domain is less than 10 μ

m.

5. A fuel cell electrode according to claim 1 wherein the redox catalyst is an enzyme.

6. A fuel cell electrode according to claim 5 wherein the enzyme is an oxido-reductase.

7. A fuel cell electrode according to claim 6 wherein the electrode is a cathode and the oxido-reductase is laccase.

8. A fuel cell electrode according to claim 1 wherein the electrode is a cathode and the electron transport mediator has a redox potential that is less than 0.3 V positive of the redox potential of the catalyst.

9. A fuel cell electrode according to claim 1 wherein the electrode is a cathode and the electron transport mediator has a redox potential that is less than 0.1 V positive of the redox potential of the catalyst.

10. A fuel cell electrode according to claim 1 wherein the electrode is an anode and the electron transport mediator has a redox potential that is less than 0.3 V negative of the redox potential of the catalyst.

11. A fuel cell electrode according to claim 1 wherein the electrode is an anode and the electron transport mediator has a redox potential that is less than 0.1 V negative of the redox potential of the catalyst.

12. A fuel cell electrode according to claim 1 wherein the electron transport mediator is selected from the group consisting of:

quinones, hydroquinones, metalloorganic complexes, conjugated unsaturated acyclic and cyclic molecules, metal ions and biological electron carriers.

13. A fuel cell electrode according to claim 1 wherein the electrode is a cathode and the electron transport mediator is 2,2′

-azinobis(3-ethylbenzothiazoline-6-sulfonate).

14. A fuel cell electrode according to claim 1, wherein said electrode produces in excess of 50 mA per cm² of projected electrode surface area.

15. A fuel cell electrode according to claim 14 having the following parameters:

a) a microdomain with about 4×

10<sup>−

9</sup> moles of a redox catalyst;

b) an electron transport mediator in a concentration of about 5×

10<sup>−

3</sup>M;

c) an effective volumetric surface area of the microporous current collector in excess of 100 cm²;

wherein all of the redox catalyst resides within about 3 μ

m of the current collector surface, and all of the current collector surface resides within 10 μ

m of a reservoir of air-saturated aqueous buffer.